Range finder for cameras



April 5, 1938. J. MIHALYI RANGE FINDER FOR CAMERAS Filed Aug. '51, 1954 2 Sheets-Sheet 1 gwuentoc:

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April ;5, 1938. J. MIHALYI RANGE FINDER FOR CAMERAS Filed Aug. 31, 1934 2 Sheets-Sheet 2 m ted A r.5,1938 2,113,301

UNITED STATES PATENT OFFICE RANGE FINDER FOR CAMERAS Joseph Mihalyi, Rochester, N. Y., assignor, by

mcsne assignments, to Eastman-Kodak Company, Jersey City, N. J., a corporation of New Jersey Application August 31, 1934, Serial No. 742,242 In Germany June 20, 1934 6 Claims. (Cl. 95-44) My invention relates to photographic cameras In the accompanying drawings in which like provided with range finders of the general type reference characters indicate like parts through* in whichyas the adjustment necessary to deterout: mine the range of the object is made, focusing of Fig. 1'is a diagrammatic view in perspective of the camera is simultaneously effected. In camthe optical system of a range finder made in ac- 5 eras of this type it is customary to employ a range cordance with the invention; finder of the split field coincidence and short base F 2 is a fragmentary view in per type. The use of a split field type range finder showing a modified form of the image erecting facilitates the bringing of the two images into System;

coincidence, but the shorter the base of the Fig. 3 shows the field of view when the split 10 range finder, other things being equal, the greatages a e et in co d e; er the difficulty of determining exactly when the Fig. 4 is a view in perspective of a camera protwo images are in coincidence. vided with a range finder in accordance with the It is an object of the present invention to proinvention;

l5 vide a range finder and focusing system .of sim- Fig. 5 is a front view of the camera shown in pie and robust construction and which, when Fig. 4 with p r f t lehsthoel'd tom y; and mounted on small cameras, may be provided with F 6 is a S e w P y ih'seetion 0f the a longer base line than has heretofore been posmounting for the camera objective with its cassible. Another object of the invention is to pror v dvide a range finder which may be employed to T p l p s mp is d i th ra flnd 20 advantage on small cameras of the folding type, er as shown in Fig. 1 consist of three right-angle According to the invention, there is combined P s d arranged to form a modiwith reflecting elements mounted on the camera fi d prism erecting System adapted to and fixed relatively at the ends of the range eeive tWO b s of g t entering the System at finder base, a lens or lens system movable acro 90 to each other, one of which is a direct beam the path of the rays proceeding to one end only and the other is a deflected beam which traverses 0 t e base of the range finder for the purpose of the base line of the finder. One end of this base bringing the images into coincidence, and means e s d r ed by t erecting Prism assemfor effecting on the one hand movement of th bly and the other is defined by a right-angle camera lens for focusing purposes, and on the P m l3 w ch r ce ves ht om he bj and 0 other hand the said movement of the range finder bends it through a angle ehdielong the base lens, these movements being brought about sie of the an e finder. multaneously and in correlation. This movable The image-forming P t 1' the range finder lens or lens system in the range finder system is p i s le opes h vin tw objectives a telescope objective and may conveniently be a d 5 f t e S me foe-a le th and a Single designated a field lens, and its movement is in Ocular Consisting 0 two ns ele ents It f r a direction parallel to the range finder base. A Viewing e dj t m s formed y the rotatable cam preferably is employed whereby the J'e Ve s l w b de d- T e Obj t focusing movement of the camera lens is transl4 positioned in the direct light beam A is of 40 mitted simultaneously and correspondingly to Such focal length that the light Passing 40 and effects this movement of the range finder h g te being twice reflected y the Prism field lens. The focusing of thegcamera may be i2, forms an inverted half image A of the field effected by movement in the direction of its axis of view on the surface between the prism l2 and of the whole objective or a part or one member t e Pr s "1- T e bje ve l5 p ed n t e only of the camera objective. base line of the range finder receives light from 5 In accordance with the invention, the camera the beam B after being defl y v Prism is preferably provided with a view finder which l3 and forms an inverted half ima at h may be of a well-known type and is disposed sepcontacting faces of the P i s It a d 0- arate of and where it will not interfere with the The two half images A and B are. adjacent range finder system. and sharply separated by the line i1 formed be- 5 The invention as well as other objects and adtween the two prisms II and I2; The size of vantages of it will be fully understood from the these images A and B may be defined by an following description when read in connection opaque diaphragm l8 which serves as a field stop with the accompanying drawings, and its scope' for the telescope systems. The focal length or will be pointed out in the appended claims. the ocular I6 is such as to take in the glass path 55 of the prism III to the focal plane at which the images A and B appear. It'will be noted that the above arrangement whereby the two beams A and B enter the erecting system on the same side makes it possible to utilize almost the entire over-all width of the range finder for the base line length.

The telescope objective lens I4 is preferably utilized for bringing the range finder images into coincidence by arranging it to be moved transversely -of its optical axis in strict accordance with the. distance for which the camera is focused. One suitable arrangement for imparting this movement to the objective lens I4 is shown in Fig. 1 as comprising a radial cam l9 rotatable with the camera objective 20 in focusing, and which, through a cam follower 2|, imparts movement in one direction to the objective l4 and its mount 22 carried by the cam follower 2|. For keeping the cam follower 2| in contact with the cam l9 and for moving the objective M in the other transverse direction, a coiled spring 23 may be provided having one end secured to the cam follower 2| and its other end anchored to a suitable part 24 of the'casing for the objective lens 20 of the camera.

The range finder construction as shown in Fig. 1 permits the use of a view finder consisting of the usual negative forward lens 25 and a rear positive lens 26 without interfering with the range finder system and without noticeably increasing the over-all size of the combined systems. As shown, the view finder consisting of the lenses 25 and -26 is positioned in the base line of the range finder, but may have its optical axis displaced vertically with respect to this base line as indicated by the double-headed arrow D.

It will be understood that, if desired, the several prisms shown in Fig. 1 may be replaced by suitably arranged mirrors, and one convenient alternative arrangement for the erecting prism assembly is shown in Fig. 2 as utilizing a surface mirror 21 in place of the prism II as shown in Fig. 1.

The telescope objectives l4 and I5 form inverted images A and B at the coincidence line H, and these images, when erected and viewed through the ocular lenses I6, will appear as shown in Fig. 3, and adjustment of. the camera objective 20 to bring these two images into coincidence by moving the telescope objective M will insure the camera being in focus for the object whose images are brought into coincidence.

The camera upon which this range finder may be mounted may be constructed in anydesired manner. The invention, however, is particularly intended for use with small folding cameras.

A preferred feature in the camera structure is,-

however, that the lens system is so formed or arranged as to permit of focusing being effected by a single member of the camera lens system, although there may be employed the more customary arrangement in which the whole lens system is movable in front of the camera casing for the purpose of adjusting the camera focus.

One complete embodiment of my invention is shown in Fig. 4 as comprising a folding camera, the body portion 28 of which is provided on its top side with a housing 29 for the various parts of the range finder and view finder. A camera lens board or casing 30 is movable to and from the camera body 28 in any suitable well-known manner and is connected thereto by a suitable light-tight bellows 3|. The mount 22 for the telescope objective lens I4 is formed integrally with the cam follower 2|, a fiat portion of which is provided with slots 32 through which extend pins 33 carried by the upper side of the camera objective casing 30 to form a sliding connection between the cam follower 2| and the casing 30. As above described, the cam follower 2| contacts with the cam I9 which is rotatable with the focusing movement of the camera objective.

The range finder housing 29 formed on the top side of the camera body 28 is provided with windows 34 and 35 which coincide respectively with the entering beams A and B. The housing 29 is also provided intermediate its ends with suitable openings in which may be mounted the lenses 25 and 26 of the view finder. It will be noted that in Fig. 4 the light'defiector for the range finder beam B consists of a plane mirror I3 which is the optical equivalent of the prism |3 shown in Fig. 1.

As is best shown in Fig. 5, which is a front view of the camera shown in Fig. 4, the cam follower 2| is resiliently held into engagement with the radial cam I9 by means of the coiled'spring 22. As shown in this figure, the camera objective 20 may be focused by rotating a focusing ring 36.

In its preferred form the camera focus is varied by adjusting a single element of the camera lens system as is shown partly in section in Fig. 6.

The camera lens 2|) may take any suitable form I and is here shown as being of the Cooke type consisting of a front element 20', a middle element 3'!- and a rear element 38. The rear element 38 is provided with a mounting ring 38 which is secured to the rear side of a shutter casing 40 (the shutter mechanism has been omitted) in any well known manner as by screw threads. On the front of the casing 40 is secured the middle lens element 31 by means of its mounting'ring 4| which is provided with an annular-threaded portion 42 adapted to receive a threaded lip 43 extending rearwardly from the focusing ring 36. It will be evident that rotation of the ring 36 will vary the spacing between the lens elements 20 and 31 to alter in a well known manner the focus. of the lens system. The lip 43 may carry the cam l9 which actuates the movable element of the range finder as above described.

In using the camera provided with the range finder as described, it is pointed toward the ob-,

ject upon which it is desired to focus the camera and the two split images of this object are viewed through the ocular l6 of the range finder, and if they are out of coincidence, as shown in Fig. 3,

the focusing ring 36 is rotated, which rotates the radial cam l9 which in turn actuates the cam follower 2| to move the beam deflecting telescope objective l4 transversely of its axis until the two images A and B are coincident, at which time the camera objective 20 will be focused for this object.

From the above description, it will be seen that my invention makes possible the use of a range finder and focusing mechanism particularly suitable for application to a folding camera and by mounting one of the telescope objectives on the lens board of the camera which is moved out from the camera body for use, makes it possible to increase the length of the base line of the range finder accordingly. It is, of course, possible to employ this range finder structure on a camera of the non-folding type in which the front is always fixed in relation to the back part thereof. The present invention also enables the mechanism for effecting the simultaneous focusing of the camera lens and the adjustment of the movable part of the range finder to be strongly and simply constructed and arranged in a compact manner.

It will be noted that my invention permits a construction making it possible to employ in the range finder an optical system which will give a magnification of the object, thereby further increasing the effective length of the base line.

Although I have illustrated and described a spiral cam with a suitable cam follower for translating focusing movement of the camera objective into transverse movement of the telescope objective lens for adjusting the. deflection of one of the range finder images, it will be understood that other suitable arrangements may be employed so long as the desired correlation between the range finder setting and the focusing of the camera objective is maintained.

Various modifications will occur to those skilled in this art wtihout departing from the spirit of my invention, the scope of which is pointed out in the appended claims.

What I claim as my invention and desire to secure by Letters Patent is:

1. In a focusing finder, the combination with a camera body, of a lens board movable to and from a fixed position in front of the camera body, a lens adjustable in said board for focusing, a base type range finder having its base line carried by the camera body and extending transversely of the optical axis of said lens, an image uniting and erecting system arranged at one end of the base line, a reflector and objective at the other end of the base line for forming an image in said system of a part of the field of view, a second objective carried by the lens board with its optical axis perpendicular to and intersecting the base line for forming in 'said system an image of a vertically adjacent part of the field of view, and a motion transmitting coupling between the adjustable lens and the second'objective said coupling being so arranged that when the camera is focused on a field of view the adjacent images will be coincident.

2. In a folding camera, a lens board movable to 1 a fixed position in front of the camera body at which the camera is operative, an adjustable lens in the board for focusing the camera, a range finder including an objective mounted on the camera body and a second objective carried by the lens board, and means coupled to the adjustable lens for moving said second objective transversely of its optical axis in accordance with the focusing adjustment of the lens.

3. In a photographic camera, a camera lens,

supporting means for the camera lens, a rotatable member for-focusing said lens, a cam carried by the rotatable member, a self-contained base line range finder mounted on the camera and having, two telescopes consisting of two objectives and a single ocular, an image uniting and erecting prism system between said objectives and the ocular, reflectors for directing the light from the objectives into said prism system, one of said objectives being positioned in the base line of the range finder and the other of said objectives being mounted on the camera lens supporting means, and means actuated by said cam for moving said other objective transversely of its optical axis.

4. A photographic camera having a focusing lens, a lens board movable to and from the body of the camera, a mount on said board for the lens having a part adjustable for focusing the lens, a range finder system for the camera including two telescope objectives and'light deflecting members cooperating to form adjacent images of adjacent parts of an object field, and an ocular for viewing the adjacent images, one of said ohjectives being carried by the movable lens board, and means actuated by said adjustable part for 4 moving the last-mentioned objective transversely of its axis in accordance with focusing movement of said lens, whereby one of the images viewed by the ocular is shifted relatively to the other image.

5. In a photographic camera having a camera body and a lens carried by a lens board which is adapted to be moved to a fixed distance in front of the camera body for use, a movable part for altering the focus of the lens, asplit field coincidence range finder mounted on the camera bodyand having a beam controlling field lens separately supported on the lens board and movable therewith, and means connected to said movable part for moving said field lens relatively to the lens board in accordance with the altered focus of the lens.

6. A photographic camera provided with an J OSEPH MIHALYI. 

